394 research outputs found
Explicit formulae in probability and in statistical physics
We consider two aspects of Marc Yor's work that have had an impact in
statistical physics: firstly, his results on the windings of planar Brownian
motion and their implications for the study of polymers; secondly, his theory
of exponential functionals of Levy processes and its connections with
disordered systems. Particular emphasis is placed on techniques leading to
explicit calculations.Comment: 14 pages, 2 figures. To appear in Seminaire de Probabilites, Special
Issue Marc Yo
Reliability testing of tendon disease using two different scanning methods in patients with rheumatoid arthritis
Objective. To assess the intra- and interobserver reliability of musculoskeletal ultrasonography (US) in detecting inflammatory and destructive tendon abnormalities in patients with RA using two different scanning methods.Methods. Thirteen observers examined nine patients with RA and one healthy individual in two rounds independently and blindly of each other. Each round consisted of two consecutive examinations, an anatomy-based examination and a free examination according to personal preferences. The following tendons were evaluated: wrist extensor compartments 2, 4 and 6, finger flexor tendons 3 and 4 at MCP level, tibialis posterior tendon and both peronei tendons. Overall, positive and negative agreements and κ-values for greyscale (GS) tenosynovitis, peritendinous power Doppler (PPD) signal, intratendinous power Doppler (IPD) signal and GS tendon damage were calculated.Results. Intraobserver κ-value ranges were 0.53-0.55 (P < 0.0005) for GS tenosynovitis, 0.61-0.64 (P < 0.0005) for PPD signal, 0.65-0.66 (P < 0.0005) for IPD signal and 0.44-0.53 (P < 0.0005) for GS tendon damage. For interobserver reliability, substantial overall agreement ranged from 80 to 89% for GS tenosynovitis, 97 to 100% for PPD signal, 97 to 100% for IPD signal and 97 to 100% for GS tendon damage. Results were independent of scanning technique.Conclusion. Intraobserver reliability for tenosynovitis and tendon damage varied from moderate for GS to good for PD. Overall interobserver reliability for tenosynovitis and tendon damage was excellent both for GS and PD. This qualitative scoring system may serve as the first step to a semi-quantitative score for tendon pathology. © The Author 2012. Published by Oxford University Press on behalf of the British Society for Rheumatology. All rights reserved
Introducing the national COPD resources and outcomes project
<p>Abstract</p> <p>Background</p> <p>We report baseline data on the organisation of COPD care in UK NHS hospitals participating in the National COPD Resources and Outcomes Project (NCROP).</p> <p>Methods</p> <p>We undertook an initial survey of participating hospitals in 2007, looking at organisation and performance indicators in relation to general aspects of care, provision of non-invasive ventilation (NIV), pulmonary rehabilitation, early discharge schemes, and oxygen. We compare, where possible, against the national 2003 audit.</p> <p>Results</p> <p>100 hospitals participated. These were typically larger sized Units. Many aspects of COPD care had improved since 2003. Areas for further improvement include organisation of acute care, staff training, end-of-life care, organisation of oxygen services and continuation of pulmonary rehabilitation.</p> <p>Conclusion</p> <p>Key Points: positive change occurs over time and repeated audit seems to deliver some improvement in services. It is necessary to assess interventions such as the Peer Review used in the NCROP to achieve more comprehensive and rapid change.</p
Relative frequencies of inherited retinal dystrophies and optic neuropathies in Southern France: assessment of 21-year data management
PURPOSE: Inherited retinal dystrophies (IRDs) and inherited optic neuropathies (IONs) are rare diseases defined by specific clinical and molecular features. The relative prevalence of these conditions was determined in Southern France.
METHODS: Patients recruited from a specialized outpatient clinic over a 21-year period underwent extensive clinical investigations and 107 genes were screened by polymerase chain reaction/sequencing.
RESULTS: There were 1957 IRD cases (1481 families) distributed in 70% of pigmentary retinopathy cases (56% non-syndromic, 14% syndromic), 20% maculopathies and 7% stationary conditions. Patients with retinitis pigmentosa were the most frequent (47%) followed by Usher syndrome (10.8%). Among non-syndromic pigmentary retinopathy patients, 84% had rod-cone dystrophy, 8% cone-rod dystrophy and 5% Leber congenital amaurosis. Macular dystrophies were encountered in 398 cases (30% had Stargardt disease and 11% had Best disease). There were 184 ION cases (127 families) distributed in 51% with dominant optic neuropathies, 33% with recessive/sporadic forms and 16% with Leber hereditary optic neuropathy. Positive molecular results were obtained in 417/609 families with IRDs (68.5%) and in 27/58 with IONs (46.5%). The sequencing of 5 genes (ABCA4, USH2A, MYO7A, RPGR and PRPH2) provided a positive molecular result in 48% of 417 families with IRDs. Except for autosomal retinitis pigmentosa, in which less than half the families had positive molecular results, about 75% of families with other forms of retinal conditions had a positive molecular diagnosis.
CONCLUSIONS: Although gene discovery considerably improved molecular diagnosis in many subgroups of IRDs and IONs, retinitis pigmentosa, accounting for almost half of IRDs, remains only partly molecularly defined
An international survey on the pragmatic management of epistaxis
Epistaxis is one of the most common ear, nose and throat emergencies. The management of epistaxis has evolved significantly in recent years, including the use of nasal cautery and packs. However, a correct treatment requires the knowledge of nasal anatomy, potential risks, and complications of treatment. Epistaxis is often a simple and readily treatable condition, even though a significant bleed may have potentially severe consequences. At present, there are very few guidelines concerning this topic. The current Survey explored the pragmatic approach in managing epistaxis. A questionnaire, including 7 practical questions has been used. The current International Survey on epistaxis management reported a relevant prevalence (21.7%), mainly during childhood and senescence, an important hospitalization rate (11.8%), the common use of anterior packing and electrocoagulation, and the popular prescription of a vitamin supplement and intranasal creams
Integrated Proteomic and Transcriptomic Investigation of the Acetaminophen Toxicity in Liver Microfluidic Biochip
Microfluidic bioartificial organs allow the reproduction of in vivo-like properties such as cell culture in a 3D dynamical micro environment. In this work, we established a method and a protocol for performing a toxicogenomic analysis of HepG2/C3A cultivated in a microfluidic biochip. Transcriptomic and proteomic analyses have shown the induction of the NRF2 pathway and the related drug metabolism pathways when the HepG2/C3A cells were cultivated in the biochip. The induction of those pathways in the biochip enhanced the metabolism of the N-acetyl-p-aminophenol drug (acetaminophen-APAP) when compared to Petri cultures. Thus, we observed 50% growth inhibition of cell proliferation at 1 mM in the biochip, which appeared similar to human plasmatic toxic concentrations reported at 2 mM. The metabolic signature of APAP toxicity in the biochip showed similar biomarkers as those reported in vivo, such as the calcium homeostasis, lipid metabolism and reorganization of the cytoskeleton, at the transcriptome and proteome levels (which was not the case in Petri dishes). These results demonstrate a specific molecular signature for acetaminophen at transcriptomic and proteomic levels closed to situations found in vivo. Interestingly, a common component of the signature of the APAP molecule was identified in Petri and biochip cultures via the perturbations of the DNA replication and cell cycle. These findings provide an important insight into the use of microfluidic biochips as new tools in biomarker research in pharmaceutical drug studies and predictive toxicity investigations
Elevated aluminium concentration in acidified headwater streams lowers aquatic hyphomycete diversity and impairs leaf-litter breakdown.
Aquatic hyphomycetes play an essential role in the decomposition of allochthonous organic matter which is a fundamental process driving the functioning of forested headwater streams. We studied the effect of anthropogenic acidification on aquatic hyphomycetes associated with decaying leaves of Fagus sylvatica in six forested headwater streams (pH range, 4.3-7.1). Non-metric multidimensional scaling revealed marked differences in aquatic hyphomycete assemblages between acidified and reference streams. We found strong relationships between aquatic hyphomycete richness and mean Al concentration (r = -0.998, p < 0.0001) and mean pH (r = 0.962, p < 0.002), meaning that fungal diversity was severely depleted in acidified streams. By contrast, mean fungal biomass was not related to acidity. Leaf breakdown rate was drastically reduced under acidic conditions raising the issue of whether the functioning of headwater ecosystems could be impaired by a loss of aquatic hyphomycete species
A Naturally Associated Rhizobacterium of Arabidopsis thaliana Induces a Starvation-Like Transcriptional Response while Promoting Growth
Plant growth promotion by rhizobacteria is a known phenomenon but the underlying mechanisms are poorly understood. We searched for plant growth-promoting rhizobacteria that are naturally associated with Arabidopsis thaliana to investigate the molecular mechanisms that are involved in plant growth-promotion. We isolated a Pseudomonas bacterium (Pseudomonas sp. G62) from roots of field-grown Arabidopsis plants that has not been described previously and analyzed its effect on plant growth, gene expression and the level of sugars and amino acids in the host plant. Inoculation with Pseudomonas sp. G62 promoted plant growth under various growth conditions. Microarray analysis revealed rapid changes in transcript levels of genes annotated to energy-, sugar- and cell wall metabolism in plants 6 h after root inoculation with P. sp. G62. The expression of several of these genes remained stable over weeks, but appeared differentially regulated in roots and shoots. The global gene expression profile observed after inoculation with P. sp. G62 showed a striking resemblance with previously described carbohydrate starvation experiments, although plants were not depleted from soluble sugars, and even showed a slight increase of the sucrose level in roots 5 weeks after inoculation. We suggest that the starvation-like transcriptional phenotype - while steady state sucrose levels are not reduced - is induced by a yet unknown signal from the bacterium that simulates sugar starvation. We discuss the potential effects of the sugar starvation signal on plant growth promotion
Exploring the transdisciplinary trajectory of suggestibility
Traditionally considered a deficiency in will power and rationality, suggestibility has proven a troublesome concept for psychology. It was forgotten, rediscovered, denounced, undermined experimentation and recently became the ambiguous issue at the centre of concern about child witness' credibility in sexual abuse cases. This paper traces the history of suggestibility to show how it raises the 'paradox of the psychosocial'. Drawing on the work of Deleuze and Stengers, and on interviews with legal practitioners, this paper demonstrates how suggestibility carries this paradox into theory, research and legal practice. It thereby opens up a transdisciplinary perspective, allowing for questions of power and knowledge to be asked as performative questions. In the spirit of a process-centred ontology for psychology, I argue that suggestibility constitutes a 'rhythm of problematization', a folding, giving a subversive insight into dynamics of subjectification and application, and offering new perspectives towards issues of children's credibility and protection
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